If your using VGA to now need to prepend your video bios to the coreboot.rom. Copy your vga bios file (vga.rom) to the ~/coreboot-v2/targets/rca/rm4100/rm4100 directory and then:

cat vga.rom coreboot.rom > bios.bin

4. At last your ready to flash bios.bin to your RM4100. If this is the first time, meaning your rm4100 still has the original bios, you need to use the method on the RM4100 Customizing website to flash otherwise you can just use flashrom.